Compound-Marker Interactions

Testosterone enanthate stimulates erythropoiesis through EPO upregulation, raising haematocrit. Levels above 54% increase thrombotic risk and require intervention.

Testosterone aromatises to estradiol via the aromatase enzyme. Managing estradiol is central to TRT optimisation, with both excess and deficiency causing symptoms.

Trenbolone is one of the most lipid-toxic anabolic steroids, suppressing HDL cholesterol by 50-70% even at moderate doses. This dramatically increases cardiovascular risk.

Anastrozole is a potent aromatase inhibitor that reduces estradiol by 70-85%. It is used to manage estrogen-related side effects on testosterone therapy, but over-use can crash estradiol to dangerously low levels.

Growth hormone is a counter-regulatory hormone to insulin, promoting gluconeogenesis and insulin resistance. Chronic use can elevate fasting glucose and HbA1c, potentially leading to type 2 diabetes.

Testosterone enanthate stimulates red blood cell production through EPO upregulation and hepcidin suppression, raising haemoglobin by 1-2 g/dL on TRT doses. Haemoglobin rises in parallel with haematocrit and is a key marker for polycythemia monitoring.

Exemestane is a suicidal (irreversible) aromatase inhibitor that reduces estradiol by 85-95%. Unlike anastrozole, it permanently inactivates aromatase enzymes, making it harder to titrate but offering a more favourable lipid profile.

Methandrostenolone (Dianabol) is a 17-alpha-alkylated oral anabolic steroid that causes dose-dependent hepatotoxicity. ALT typically rises 2-5x the upper limit of normal during use, reflecting hepatocellular stress.

Oxymetholone (Anadrol) is one of the most hepatotoxic oral anabolic steroids. ALT can rise 5-20x the upper limit of normal, with peliosis hepatis and cholestatic jaundice being documented risks at prolonged high doses.

Stanozolol (Winstrol) is a 17-alpha-alkylated oral steroid with moderate hepatotoxicity. ALT typically rises 2-4x the upper limit of normal. Stanozolol is notable for having a worse impact on lipids than on the liver.

Oxandrolone (Anavar) is the mildest oral anabolic steroid for hepatotoxicity. ALT typically rises 1.5-3x the upper limit of normal. It remains 17-alpha-alkylated but is used at lower doses and has a more favourable safety profile than other oral steroids.

Superdrol (methyldrostanolone) is one of the most hepatotoxic oral anabolic steroids. ALT can rise 10-30x the upper limit of normal within 2-3 weeks. Cholestatic jaundice is a well-documented risk even at standard doses.

Halotestin (fluoxymesterone) is a very hepatotoxic 17-alpha-alkylated oral steroid. ALT typically rises 5-15x the upper limit of normal. It is used only briefly before competition for its potent androgenic and aggression-enhancing effects.

Exogenous T3 (liothyronine/Cytomel) suppresses TSH through negative feedback on the hypothalamic-pituitary-thyroid axis. TSH can drop to near-zero during use. Recovery of endogenous thyroid function after discontinuation typically takes weeks to months.

Growth hormone increases the peripheral conversion of T4 to T3 by upregulating type 1 deiodinase. Free T3 levels rise while free T4 may decline. This interaction is clinically relevant when GH is combined with exogenous T3.

Semaglutide is a GLP-1 receptor agonist that reduces HbA1c by 1.0-1.8% through enhanced insulin secretion, suppressed glucagon, and delayed gastric emptying. It is increasingly used in bodybuilding contexts for fat loss and metabolic optimization.

Semaglutide reduces ALT by 10-30% over 3-6 months through reduction of hepatic steatosis (fatty liver). This is a beneficial effect, making semaglutide one of the few PEDs that improves rather than worsens liver markers.

Trenbolone raises serum creatinine through increased muscle mass (higher creatine turnover) and possible direct renal tubular effects. Cystatin C is a more reliable marker for assessing true kidney function (GFR) on trenbolone.

Nandrolone decanoate (Deca-Durabolin) increases prolactin through progesterone receptor agonism and modulation of dopamine pathways. Elevated prolactin causes sexual dysfunction, gynecomastia, and mood disturbances. Cabergoline is the first-line treatment.

All androgens suppress HDL cholesterol via hepatic lipase activation. Testosterone at TRT doses typically reduces HDL by 10-20%, while supraphysiological doses cause 20-40% reduction. The impact is less severe than with oral steroids or trenbolone.

Testosterone drives erythropoiesis, increasing iron demand for haemoglobin synthesis. Ferritin drops as iron stores are consumed, and repeated phlebotomy accelerates the decline into functional or absolute iron deficiency.

Testosterone suppresses hepcidin, increasing iron absorption and mobilisation. Serum iron initially rises, but chronic EPO-driven erythropoiesis and phlebotomy can eventually deplete circulating iron as stores are exhausted.

Testosterone suppresses hepcidin, increasing iron availability and raising transferrin saturation. In iron-replete men, saturation can exceed 45%, triggering hemochromatosis workup. In men undergoing phlebotomy, saturation may drop as iron stores are depleted.

Testosterone enanthate increases DHT through 5-alpha reductase conversion. The magnitude depends on dose and delivery method, with implications for hair loss, prostate health, and acne.

Exogenous testosterone and all anabolic-androgenic steroids suppress hepatic SHBG production. SHBG drops within 1-2 weeks of starting TRT, increasing the free testosterone fraction. The degree of suppression is dose-dependent and more aggressive with oral 17-alpha-alkylated steroids.

Exogenous testosterone suppresses LH to undetectable levels via negative feedback on the hypothalamic-pituitary-gonadal axis. This is universal at all TRT and supraphysiological doses and is the primary mechanism of TRT-induced infertility.

Stanozolol is the most lipid-destructive anabolic steroid documented in controlled trials, suppressing HDL by 33-70% and crashing HDL2 (the most protective subfraction) by up to 71% at doses as low as 6 mg/day.

Oxandrolone (Anavar) suppresses HDL via the same 17-alpha-alkylated hepatic lipase mechanism as stanozolol, but with moderate rather than severe effect. Despite its reputation as a 'mild' oral, oxandrolone is not lipid-neutral and produces clinically significant HDL reduction at bodybuilding doses.

Nandrolone decanoate (Deca-Durabolin) has the most favourable lipid safety profile of commonly used anabolic steroids. At moderate doses, HDL impact is minimal to modest, making it a preferred injectable for athletes prioritising cardiovascular harm reduction.

Methandrostenolone (Dianabol) suppresses HDL significantly as a 17-alpha-alkylated oral steroid, but its heavy aromatisation to estradiol provides partial mitigation compared to non-aromatising orals. Net effect is still significant HDL suppression of 30-50% at typical doses.

Oxymetholone (Anadrol) produces severe HDL suppression alongside extreme hepatotoxicity, creating one of the most atherogenic lipid profiles of any commonly used anabolic steroid. Case reports document HDL below 20 mg/dL during typical bodybuilding doses.

Clomiphene citrate blocks estrogen receptors at the pituitary, removing negative feedback and stimulating LH release. This is the primary mechanism behind its use in post-cycle therapy and treatment of male hypogonadism.

Clomiphene acts as an estrogen agonist at the liver, directly stimulating hepatic SHBG production. This can mask testosterone recovery during PCT by binding free testosterone even as total testosterone levels normalize.

Clomiphene blocks estrogen receptors but does not reduce circulating estradiol levels. Estradiol often rises during clomiphene therapy because increased LH stimulates testosterone production, which aromatizes to estradiol.

HCG mimics LH by binding the same receptor on Leydig cells, stimulating testosterone production. However, exogenous HCG suppresses endogenous LH through negative feedback, as the resulting testosterone rise signals the pituitary to reduce its own LH output.

Nandrolone decanoate profoundly suppresses LH through dual androgen receptor and progesterone receptor-mediated negative feedback at the hypothalamus and pituitary. Suppression is deeper and more prolonged than with testosterone alone, with recovery often requiring months after the last injection.

Trenbolone elevates prolactin through progestogenic activity at pituitary lactotroph cells. Elevated prolactin can independently suppress LH, worsen gynecomastia risk, and impair sexual function, making it a critical marker to monitor during and after trenbolone use.

HCG stimulates testicular Leydig cell aromatase, causing a disproportionate rise in estradiol relative to testosterone. At fertility-range doses, estradiol can peak at more than four times baseline within 24 hours, making E2 monitoring essential during HCG use.

HCG mimics LH at testicular Leydig cells, stimulating intratesticular testosterone production. The primary goal is maintaining intratesticular testosterone for spermatogenesis rather than raising serum testosterone, and the optimal dose is the lowest that preserves intratesticular levels.

Enclomiphene is the pure estrogen-antagonist isomer of clomiphene. By blocking estrogen receptors at the hypothalamus and pituitary, it removes negative feedback and causes a sustained, dose-dependent rise in endogenous LH without the estrogenic side effects of the zuclomiphene component in racemic clomiphene.

Enclomiphene raises FSH through the same pituitary SERM mechanism that elevates LH. The FSH response is what makes enclomiphene and other SERMs uniquely valuable for fertility: FSH drives spermatogenesis via Sertoli cells, an effect HCG cannot replicate.

Enclomiphene raises testosterone by stimulating endogenous LH production, which drives Leydig cell steroidogenesis. In hypogonadal men, enclomiphene raised testosterone comparably to testosterone gel while preserving spermatogenesis, something exogenous testosterone cannot do.

Gonadorelin is synthetic GnRH that stimulates pulsatile LH and FSH release from the anterior pituitary. It maintains the entire HPG signalling cascade, offering a physiologically elegant alternative to HCG with less estradiol elevation and no Leydig cell desensitisation.

Exogenous growth hormone directly stimulates hepatic IGF-1 production, raising circulating levels in a dose-dependent manner. IGF-1 is the primary biomarker used to gauge GH activity, and sustained supraphysiological levels carry risks including organ enlargement and potential cancer promotion.

Growth hormone induces chronic insulin resistance that elevates average blood glucose over time, which is reflected in glycated haemoglobin (HbA1c). HbA1c is a more reliable indicator of GH-related metabolic harm than single fasting glucose readings because it captures cumulative glucose exposure over 2-3 months.

Growth hormone induces peripheral insulin resistance, forcing pancreatic beta cells to secrete more insulin to maintain glucose homeostasis. Fasting insulin rises before fasting glucose does, making it the earliest detectable warning sign of GH-related metabolic disruption.

MK-677 is a ghrelin mimetic that stimulates endogenous GH secretion, producing sustained 24-hour GH elevation rather than the normal pulsatile pattern. This continuous GH exposure drives persistent insulin resistance and glucose elevation through the same mechanisms as exogenous GH, with the added metabolic effects of ghrelin receptor activation.

MK-677's continuous GH stimulation creates sustained free fatty acid elevation that drives persistent compensatory hyperinsulinemia. Fasting insulin and HOMA-IR rise as pancreatic beta cells work harder to maintain glucose homeostasis, making fasting insulin the earliest warning signal of MK-677-related metabolic stress.

MK-677 stimulates sustained GH secretion via ghrelin receptor activation, producing dose-dependent IGF-1 elevation that persists throughout the 24-hour dosing interval. Unlike pulsatile GH secretagogues, MK-677's continuous GH stimulation drives IGF-1 into the upper physiological or supraphysiological range.

MK-677 raises HbA1c through sustained GH-mediated insulin resistance and elevated fasting glucose. The Nass et al. (2008) two-year RCT documented a 0.2% HbA1c increase compared to placebo, confirming a clinically measurable long-term glucose impact.

Ipamorelin is a selective GHRP that stimulates pulsatile GH release, producing dose-dependent IGF-1 elevation with a cleaner side-effect profile than other GH secretagogues. It does not affect cortisol, ACTH, prolactin, or gonadotropins.

Sermorelin carries a documented 6.5% incidence of subclinical hypothyroidism per its FDA prescribing information. GH stimulation accelerates T4-to-T3 conversion, potentially depleting T4 and triggering compensatory TSH elevation.

Tesamorelin is the only FDA-approved GHRH analog and produces dose-dependent IGF-1 elevation. The NEJM trial documented an 81% IGF-1 increase at 2 mg/day, with a favourable metabolic profile compared to other GH secretagogues.

Tesamorelin is the only GH secretagogue with documented triglyceride-lowering effects. The NEJM trial showed a 50 mg/dL reduction in triglycerides at 2 mg/day, along with improvements in total cholesterol-to-HDL ratio.

Boldenone undecylenate (Equipoise) is considered the most disproportionately erythropoietic anabolic steroid per unit of androgenic activity. Its long-acting undecylenate ester creates a sustained EPO stimulus that drives haematocrit higher than testosterone at comparable androgenic doses.

Boldenone undecylenate drives significant haemoglobin elevation through sustained EPO stimulation, typically producing greater haemoglobin increases than testosterone at comparable androgenic doses. Values above 18.5 g/dL are common in users running extended boldenone cycles.

Nandrolone decanoate (Deca-Durabolin) raises haematocrit through EPO stimulation and hepcidin suppression. Its erythropoietic effect is moderate relative to boldenone and high-dose testosterone, but it potentiates exogenous EPO and compounds erythropoiesis when stacked with other androgens.

Trenbolone acetate stimulates erythropoiesis through potent androgen receptor activation without aromatisation to oestrogen. The absence of oestrogen-mediated plasma volume expansion creates a disproportionately elevated haematocrit relative to total blood volume, worsening blood viscosity.

Stanozolol enhances platelet aggregation through androgen receptor-mediated upregulation of platelet surface receptors and intracellular signalling pathways. Unlike most AAS, stanozolol's main haematological risk is on the coagulation axis rather than haematocrit elevation.

Oxymetholone (Anadrol) is the only anabolic steroid with an FDA approval specifically for treating anaemia caused by deficient red blood cell production. At therapeutic doses it substantially raises haemoglobin, but at bodybuilding doses (50-150 mg/day) this erythropoietic effect compounds with direct haematological toxicity and hepatotoxicity.

Anastrozole suppresses HDL by inhibiting aromatase and reducing estradiol, which normally restrains hepatic lipase activity. Lower estradiol accelerates HDL catabolism independently of the direct androgenic pathway, adding a second HDL-suppressive mechanism on top of whatever testosterone is already doing.

Boldenone (Equipoise) suppresses HDL through a dual pathway: direct androgenic hepatic lipase upregulation and indirect estradiol lowering from its aromatase-competing metabolite. The reputation of EQ as lipid-mild is partially misleading, as the estradiol-lowering effect creates a second independent HDL-suppressive mechanism.

Superdrol produces some of the most severe HDL suppression documented in bodybuilding, routinely crashing HDL to single digits within 2-4 weeks. As a non-aromatising 17-alpha-alkylated oral, it combines maximum first-pass hepatic androgenic loading with zero estrogenic counterbalance.

Halotestin may produce the single worst lipid profile of any commonly used AAS. As an extremely potent, non-aromatising, fluorinated 17-alpha-alkylated oral, it delivers maximum hepatic androgenic stimulation with zero estrogenic counterbalance and prolonged hepatic exposure due to fluorine-enhanced metabolic stability.